[PX-12 Promoting Apoptosis of Multiple Myeloma Cell Line H929 Induced by Bortezomib]

To study the effect of PX-12 on apoptosis of multiple myeloma (MM) cell line induced by bortezomib.

MM cell line H929 cells were divided into PX-12 group, bortezomib group, combination group, and control group. 5.0 μmol/L PX-12, 20 nmol/L bortezomib, combination of the two drugs, and DMSO were given to the above mentioned group, respectively. After culture for 24, 48, and 72 hours, the changes of cell viability were observed, the MM cell activity was detected by MTT method, and the cell cycle distribution and apoptosis of each group was detected by flow cytometry. The intracellular ROS level was measured by H₂DCFDA probe labeling.

MTT assay showed that after culture for 72 hours, the activity of H929 cells in PX-12 group (P<0.05) and bortezomib group (P<0.01) was significantly lower than that in the control group, while that in the combination group was decreased most significantly (P<0.01). After culture for 48 hours, cells in G1 phase in PX-12 group was decreased to 40%, while cells in S phase and G₂/M phase was increased to 28% and 40%, respectively. The cells in bortezomib group also showed a similar distribution after being treated. After treated with PX-12 and bortezomib, the cells in G1 phase were decreased significantly to 19% and 12% in S phase, but increased significantly to 68% in G₂/M phase, which was significantly different from PX-12 group and bortezomib group (P<0.01). After culture for 72 hours, the apoptosis rate was 71.3% in the combination group, which was significantly higher than that in PX-12 group, bortezomib group, and control group (20.6%, 33.3%, 10.6%)(P<0.01). After culture for 24 hours, the intracellular ROS level in the combination group was 12015±430.2, which was higher than that in the PX-12 group, bortezomib group, and control group (6729±352.8, 2651±228.3, 1098±164.6, respectively) (P<0.01).

PX-12 can increase the apoptosis of MM cell line H929 induced by bortezomib, which may be caused by increasing of ROS level.